package jdbc;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

/**
 * 执行关联查询
 */
public class JDBCDemo6 {
    public static void main(String[] args) {
        try (Connection con = DBUtil.getConnection()){
            Statement stmt = con.createStatement();
            /*
                查看每个班级以及对应的班主任信息
                SELECT c.name,c.floor,t.name,t.title,t.salary
                FROM class c
                JOIN teacher t ON c.teacher_id=t.id
             */
            String sql = "SELECT c.name,c.floor,t.name,t.title,t.salary " +
                         "FROM class c " +
                         "JOIN teacher t ON c.teacher_id=t.id";
            ResultSet rs = stmt.executeQuery(sql);
            while(rs.next()){
//                String cName = rs.getString("c.name");
//                int cFloor = rs.getInt("c.floor");
//                String tName = rs.getString("t.name");
//                String tTitle = rs.getString("t.title");
//                int tSalary = rs.getInt("t.salary");
                //也可以通过指定字段下标获取，但是数据库中下标从1开始
                String cName = rs.getString(1);
                int cFloor = rs.getInt(2);
                String tName = rs.getString(3);
                String tTitle = rs.getString(4);
                int tSalary = rs.getInt(5);
                System.out.println(cName + " " + cFloor + " " + tName + " " + tTitle + " " + tSalary);
            }

        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}







